首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   70篇
  免费   0篇
  国内免费   1篇
化学   49篇
力学   1篇
数学   20篇
物理学   1篇
  2020年   1篇
  2017年   1篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   6篇
  2012年   3篇
  2011年   3篇
  2009年   1篇
  2008年   1篇
  2007年   5篇
  2005年   3篇
  2004年   4篇
  2003年   7篇
  2001年   2篇
  2000年   6篇
  1996年   5篇
  1992年   1篇
  1989年   1篇
  1988年   1篇
  1986年   3篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1969年   2篇
  1968年   3篇
  1967年   1篇
  1966年   2篇
排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
Potential Analysis - We prove well-posedness results for the Dirichlet problem in $\mathbb {R}^{n}_{+}$ for homogeneous, second order, constant complex coefficient elliptic systems with boundary...  相似文献   
2.
We study the efficiency of the greedy algorithm for wavelet bases in Lorentz spaces in order to give the near best approximation. The result is used to give sharp inclusions for the approximation spaces in terms of discrete Lorentz sequence spaces.  相似文献   
3.
Abstract

In our studies of the stability constants of metal complexes, we have investigated a number of macrocyclic ligands with pendant donor groups. The ligands are characterized by the fact that they have nitrogen donors in the macrocyclic ring and oxygen or sulfur donors in the pendant arms. These ligands represent seven different macrocycles, and by varying the pendant donor groups, ten different ligands are indicated. The affinities of these ligands for fifteen metal ions will be described. The Fe(III) complex of triazanonane with o-hydroxypyridyl or o-hydroxybenzyl pendant donor groups are the most stable ferric complexes ever reported. The In(III) complex of triazacyclononane with pendant mercaptoethyl donor groups, is exceptionally stable. Also, the Ca(II) complex of DOTA probably has the highest stability of any calcium(II) complex. These, and other comparisons will be made on the basis of the thermodynamic stability constant data for the ligands described.  相似文献   
4.
The Oriented-Eddy Collision (OEC) model treats turbulent flow as a non-Newtonian fluid where the average behavior of turbulence is modeled as a collection of interacting fluid particles which have inherent orientation. The model is derived from the two-point velocity correlation transport equation, and has the form of a collection of Reynolds-stress transport equations, with one set of transport equations for each representative eddy direction. The addition of eddy orientation information adds important physics to the model and allows the model to represent structural (two-point) information about the turbulence. This structural information is sufficient to allow the model to capture the effect of external forces and imposed mean strains (such as rapid distortion theory) exactly. The only physical effects that must be empirically modeled are those that are due to turbulence-turbulence interactions, referred to as eddy collisions. The performance of the model in a number of canonical flow situations is presented.  相似文献   
5.
6.
This is the fourth article of our series. Here, we study weighted norm inequalities for the Riesz transform of the Laplace–Beltrami operator on Riemannian manifolds and of subelliptic sum of squares on Lie groups, under the doubling volume property and Gaussian upper bounds.   相似文献   
7.
8.
9.
The host-guest relationships of the complexes of the cryptand ligands O-BISTREN and C-BISTREN, and of the analogous macrocyclic ligand BISDIEN are compared. The affinities of their binuclear copper(II) complexes for the bridging ligands (OH, F) as cascade type guests (i.e., guests of guests) are reported. The ability of the dicobalt(II)-BISDIEN complex to coordinate dioxygen and an additional bifunctional guest simultaneously, leads to the possibility of a new type of catalysis occurring within the cavity of a macrocyclic complex.  相似文献   
10.
Single p-toluic acid pendant groups were attached to 1,4,7,10,13-pentaazacyclopentadecane (15aneN5) and 1,4,8,11-tetraazacyclotetradecane (cyclam) to prepare bifunctional reagents for radiolabeling monoclonal antibodies with (64,67)Cu. The ligands are 1,4,7,10,13-pentaazacyclopentadecane-1-(alpha-1,4-toluic acid) (PCBA) and 1,4,8,11-tetraazacyclotetradecane-1-(alpha-1,4-toluic acid) (CPTA). For the parent macrocycles and their pendant arm derivatives, the 1:1 Cu(2+) complexes dissociate only below pH 2. At pH 0.0 and 25 degrees C the CPTA-Cu complex has a half-life toward complete dissociation of 24 days. A new approach was developed for the estimation of the Cu(2+) stability constant for the kinetically robust CPTA. All other formation constants were determined at 25.0 degrees C with batch spectrophotometric techniques. Potentiometric titrations were used to determine the protonation constants of the macrocyclic ligands as well as of the metal chelates. The protonation constants, stability constants, and pM's are discussed in terms of both molecular mechanics calculations and the ligands' potential applicability as copper(II) radiopharmaceuticals.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号